<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
div {
/*我们用css 边框可以模拟三角效果*/
width: 0;
height: 0;
border-top: 10px solid red;
border-right: 10px solid green;
border-bottom: 10px solid blue;
border-left: 10px solid pink;
}
p {
width: 0;
height: 0;
border-style: solid;
border-width: 10px;
border-color: transparent transparent transparent red;
font-size: 0;
line-height: 0;
}
</style>
</head>
<body>
<div></div>
<p></p>
</body>
</html>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
div {
position: relative;
width: 200px;
height: 100px;
background-color: pink;
margin: 100px auto;
}
p {
position: absolute;
top: -40px;
left: 50%;
margin-left: -20px;
width: 0;
height: 0;
border-style: solid;
border-width: 20px;
border-color: transparent transparent pink transparent;
font-size: 0;
line-height: 0;
}
</style>
</head>
<body>
<div>
<p></p>
</div>
</body>
</html>
